Power converter arrangements are electrical circuit arrangements for the conversion of a direct electric current voltage (D.C.) into an alternating current voltage (A.C.) (inverters) and/or for the conversion of an A.C. voltage into a D.C. voltage (rectifiers). Inverters are used, for example, in the field of regenerative energy sources, in order to permit the infeed of a D.C. voltage generated by a photovoltaic installation or similar into an A.C. system. Inverters of this type are also required, for example, for battery-powered standby power supply systems, in which the D.C. voltage delivered by the battery is converted into an A.C. voltage, which can then be fed into the standby grid system. In addition, rectifiers are applied, for example, for the charging of a battery or a battery arrangement which is supplied by an A.C. voltage source. In addition, combinations of rectifiers and inverters are specifically used in electric vehicles. During traveling, for example, a D.C. voltage delivered by a battery is converted into a controlled A.C. voltage, which powers a vehicle drive system. During braking, the electrical drive system then acts as a generator and generates an A.C. voltage which, further to rectification in a power converter circuit, can be used to charge the battery.
In existing power converters, power modules are used which employ a planar arrangement of power semiconductor chips on a substrate, generally of a ceramic material. Accordingly, the printed conductors for the connection of said semiconductor chips are, by definition, also configured in a planar arrangement. Accordingly, the arrangement of printed conductors is restricted to two dimensions. This two-dimensional arrangement is associated, in some cases, with relatively long current paths. Moreover, in some cases, the supply and return conductors surround relatively large surface areas. These two effects are associated with an in-service increase in the stray inductance of a power converter arrangement of this type. This has a negative impact upon the switching performance of the power semiconductors. In these cases, the power semiconductors used, for example diodes or IGBTs (Insulated Gate Bipolar Transistors), have higher switching losses, and heat up significantly as a result. In this case, the cooling circuit will therefore need to be dimensioned to a corresponding magnitude. The capacity of a power converter of this type is therefore less dependent upon the semiconductor chips used than upon the cooling facilities available. The more effective the cooling of the power converter, the higher the capacity available.